A typical fiber optic cable includes a fiber optic connector at each end. Each fiber optic connector typically includes a precision molded component called a ferrule (e.g., an MT ferrule) which precisely positions an end of an optical fiber of the fiber optic cable. In general, when a connector of a first fiber optic cable connects with a connector of a second fiber optic cable, an end of an optical fiber of the first fiber optic cable aligns with an end of an optical fiber of the second fiber optic cable in order to form an optical connection that is capable of conveying light from one cable to the other.
Such a connection is typically a source of light energy loss. In particular, any imperfections or small particles of dirt on the ends of the optical fibers will tend to reduce the amount of the light energy that passes from one cable to the other. As the amount of imperfections (e.g., scratches) and dirt increases at the optical fiber ends, less and less light energy passes from one cable to the other. In extreme situations, the amount of light energy loss is so great that light detection circuitry at the end of the fiber optic pathway is no longer able to detect the light signal.
Some fiber optic connectors connect to each other through an adaptor (i.e., a coupling) which aligns and holds the connectors together. One type of adaptor (hereinafter called a hinged-cover adaptor) includes hinged covers for protecting fiber ends within the fiber optic connectors. The hinged-cover adaptor works as follows.
Initially, a first fiber optic connector inserts into an opening at one end of the hinged-cover adaptor. The opening leads to an adaptor cavity within the adaptor. As the first fiber optic connector inserts into the opening, the first fiber optic connector pushes against a hinged cover that covers the opening. In response, the hinged cover swings open toward the center of the adaptor cavity, and the hinged-cover adaptor fits over and attaches to the first fiber optic connector. The hinged cover remains open toward the center of the adaptor cavity while the hinged-cover adaptor remains attached to the first fiber optic connector.
At this time, a second hinged cover at the opposite end of the hinged-cover adaptor covers the first fiber optic connector. Accordingly, if the first fiber optic connector is active (i.e., if pulses of light emanate from the fiber optic connector), the pulses of light will strike the second hinged cover at the opposite end of the hinged-cover adaptor rather than escape from the hinged-cover adaptor and possibly cause eye injury.
Next, a second fiber optic connector inserts into an opening at the opposite end of the hinged-cover adaptor. As the second fiber optic connector inserts into the opening, the second fiber optic connector pushes against the second hinged cover which covers the opening. In response, the second hinged cover swings toward the center of the adaptor cavity and toward the first fiber optic connector. The hinged-cover adaptor eventually fits over and attaches to the second fiber optic connector such that the ends of the first and second fiber optic connectors contact each other to form a fiber optic connection. As with the first hinged cover, the second hinged cover remains open while the hinged-cover adaptor remains attached to the second fiber optic connector.
Unfortunately, there are deficiencies with the above-described conventional approach to connecting two fiber optic connectors using a hinged-cover adaptor. In particular, when the hinged-cover adaptor is fitted over and attached to a first fiber optic connector and a second fiber optic connector subsequently inserts into the hinged-cover adaptor to form a fiber optic connection with the first fiber optic connector, the second fiber optic connector pushes a hinged-cover toward the first fiber optic connector. Any dirt or debris (e.g., dust) residing on the hinged-cover gets pushed into the adaptor cavity and onto the fiber end of the first fiber optic connector. Accordingly, the fiber optic connection formed between the first and second fiber optic connectors is prone to light energy loss due to the introduction of dirt and debris. Moreover, such dirt and debris tends to collect within the adaptor cavity (e.g., becomes held within the adaptor cavity by the hinged covers) over time increasing the likelihood of forming an unreliable fiber optic connection the more often connectors are inserted, removed and reinserted. In extreme situations, the dirt and debris accumulates to the point that it blocks the light signal between the fiber optic connectors thus destroying the fiber optic connection.
In contrast to the above-identified conventional approach to connecting fiber optic connectors using a hinged-cover adaptor, the invention is directed to techniques for controlling access to an optical interface using a shutter that moves away from the optical interface when exposing the optical interface. Such movement away from the optical interface avoids pushing dirt and debris toward the optical interface when the shutter exposes the optical interface to form an optical connection. Such operation keeps the optical interface clean as well as prevents light from inadvertently escaping from the optical interface that could otherwise cause eye injury (e.g., due to the light intensity).
One arrangement is directed to an optical connection system having a first optical connector and a second optical connector. The first optical connector has a connector body, an optical interface disposed within the connector body, a shutter, and a shutter controller that attaches the shutter to the connector body and that permits the shutter to move between a first position that covers the optical interface and a second position that exposes the optical interface. The second optical connector has a connector body that defines an actuator. The actuator is configured to (i) move the shutter away from the optical interface such that the shutter moves from the first position that covers the optical interface to the second position that exposes the optical interface when the second optical connector connects with the first optical connector, and (ii) maintain the shutter in the second position when the second optical connector remains connected with the first optical connector. Since the shutter moves away from the optical interface rather than toward the optical interface, any dirt and debris on the shutter is drawn away from the optical interface. This operation is superior to that of the conventional hinged-cover adaptor approach in which dirt and debris on the adaptor covers is pushed into the adaptor cavity and toward the fiber end of a fiber optic connector. Additionally, the shutter covers the optical interface to provide eye safety in situations where the optical interface is active (e.g., when the optical interface is an end of a fiber optic cable which is transmitting a signal), even when the optical connectors are disconnected from each other.
In one arrangement, the optical interface of the first optical connector includes a portion of an optical fiber having a center axis. In this arrangement, the shutter controller is configured to allow the shutter to move in a direction that is substantially perpendicular to the center axis of the portion of the optical fiber. In particular, the shutter defines a surface that extends along a plane, and the shutter controller is configured to allow the shutter to move in a direction that is substantially parallel with the plane. Such movement of the shutter is essentially sideways relative to the optical interface thus allowing the first and second optical connectors to engage each other unhindered by the shutter.
In one arrangement, the shutter controller has spring portions that compress when the shutter moves from the first position to the second position. The spring portions compress in order to push the shutter back over the optical interface in the event that the first and second optical connectors disconnect from each other. Preferably, the shutter and the shutter controller form a single contiguous member (e.g., plastic, metal, etc.) in order to form a simple, low cost component.
In one arrangement, the shutter controller is configured to lift at least an edge of the shutter away from the optical interface as the shutter slides sideways relative to the optical interface such that the shutter is free of contact with the optical interface. Accordingly, the shutter does not scratch or scuff the optical interface (i.e., does not create imperfections on the optical interface that would act as a source of light energy loss) as it moves to expose the optical interface to form an optical connection.
The features of the invention, as described above, may be employed in fiber optic connection systems, devices and methods such as those of Teradyne, Inc. of Boston, Mass.